The constant further development in the field of electronics results in increasingly efficient electronic circuits that are employed in a plurality of regions and hence require a corresponding supply with appropriate voltages and currents. In the development of new efficient circuits, attention is also paid to an increasing miniaturization of electronic components, thus permitting an increasingly broad application of electronic control and power circuits in many fields. With proceeding miniaturization, however, a compact and efficient voltage supply is required, which is provided, for example, in the form of clocked circuits. With clocked power supplies, a high flexibility in the adaptation of output voltages required for operating electronic circuits relating to the available input voltages is important. In mobile applications, for example, the available supply voltages are present in the form of common battery or accumulator voltages which are not necessarily suited for the operation of electronic circuits and must be adapted accordingly. Typically, output voltages of batteries or accumulators vary over their typical service lives and decrease with increasing age. Thus, adapting the provided voltages and reducing voltage fluctuations are also of great importance in the development of new efficient electronic circuits.
A further important issue in the development of efficient electronic circuits is a reliable and stable operation, and a power consumption over a large power range, preferably without major losses. Therefore, in any development phase, it is also an object to further reduce the power loss of electronic circuits, components and/or parts.
Inductive components, for example storage inductors, interference inductors, transformers etc., represent important components of electronic circuits. The latter largely also govern the costs of electronic circuits and components since in the production of magnetic cores, typically expensive materials and complicated production processes are required to ensure desired magnetic properties or a desired magnetic behavior and provide a sufficient controllability of magnetic cores over the complete power range. Furthermore, a volume corresponding to the size of the inductive component is required on pertaining printed circuit boards and in respective housings, so that a realization of entire compact setups is getting ever more complicated with increasing miniaturization. Here, of course, high efficiency is also important, i.e. a preferably low generation of power loss. This requires, for example, an inductive component with a good magnetic coupling of individual windings with respect to each other, a reduction of leakage fluxes, a good magnetic shielding to the outside and an improved thermal behavior since the thermal loss of sides of the inductive component represents an essential proportion in power loss and may require further cooling. Further requirements to be taken into account are, for example, given by, depending on the applied voltages, a necessary insulation strength and an accordingly good mechanical stability and resistance to most diverse environmental influences. This is in particular true for a plurality of applications, for example in mobile applications, such as in the field of portable units, applications in the automotive industry, and the like.
A reduction of thermal losses may be achieved, among other things, by avoiding eddy currents in magnetic cores and/or windings. From document US 2002/0132136 A1, an alternating arrangement of magnetic plates and insulating films is known, for example.
Document EP 1 501 106 B1 shows a ferrite core which is produced by gluing segments of pressed ferrite tablets to each other. The segments are each separated by a magnetic insulator. The term “magnetic insulator” describes a material with a relative permeability of approx. one (relative permeability of vacuum). These magnetic insulators act as distributed air gaps.
By dividing one large air gap into several small air gaps, the magnetic lines of force are better guided in the core. While the insulating films or magnetic insulators may thereby counteract the formation of eddy currents in the arrangement, leakage fluxes are only partly suppressed and a low-loss guidance of a magnetic flux is only partially achieved. Furthermore, these known arrangements lead to “bulges” of the magnetic field at the films or insulators which are provided in a winding provided over the arrangement or in lines provided near the magnetic arrangement, induce voltage and thus may cause current flow.
Accordingly designed well-known cores have a number of further disadvantages. For example, by the insulating portions (by means of insulating films or insulators) which interrupt the magnet portions in the core, heat conduction, and thus a dissipation of heat from the core, is only insufficiently achieved within the core. The thermal resistance of the insulating portions is often too high to ensure a desired heat flow towards portions that dissipate the heat to the environment or a connected heat reservoir and thus a corresponding dissipation of heat.
Starting from the well-known arrangements, it is an object of the present invention to provide a magnetic core having a good thermal behavior. It is in particular an object to provide a magnetic core having an improved conduction of heat along the magnetic core.